The present invention relates to an image processing apparatus and an image processing method with which an image is processed for communicating image data with a high quality between different types of apparatuses through a network line, such as a public telephone line or a LAN. Further, the present invention is also related to color facsimile machines, or to transmission/reception of images on the Internet.
In recent years, image communication using a public telephone line or a LAN has been widely performed, in addition to facsimile communication. A variety of apparatuses for communicating image data have been employed, for example, personal computers, composite digital copying machines and network printers, in addition to facsimile machines. Moreover, color apparatuses of the foregoing types have been used, thus resulting in color facsimile machines and color printers being used mainly.
When image data is communicated between apparatuses of different types, the following process is usually employed: the type of a supplied image of an original document is determined; the overall image is subjected to an image process adaptable to the original document; and then processed image data is transmitted to a transmission-side apparatus. When the overall body of the image of the original document is collectively treated, no problem arises if the image of the original document is composed of image data having one type of attribute, for example, if the image is composed of only characters or only photographs. However, there arises a problem if the image is composed of data having plural attributes, for example, a mixed image having characters and photographs. When, for example, data of a mixed image having characters and photographs is compressed, character portions and photograph portions are similarly subjected to the compressing process. Therefore, a compression ratio of either of the character portions or the photograph portions is reduced depending on the employed compressing method. As an alternative to this, the image quality deteriorates.
When adaptation to a receiving apparatus is attempted to be made or when the quantity of data which must be transmitted is required to be reduced, image data is sometimes subjected to a resolution converting process. If a portion required to be transmitted with a high image quality exists in data, the overall body of the image must be transmitted with a high resolution. Thus, the quantity of data which must be transmitted cannot be reduced. If the image is required to quickly be transmitted in a real time manner, the image must be transmitted with a low resolution. In the foregoing case, the image quality deteriorates excessively.
In view of the foregoing, an object of the present invention is to provide an image processing apparatus and an image processing method with which an image can be transmitted at higher speed with a high quality. Particularly, in the present invention, resolution which is one of components of an image-structure is considered.
The present invention has a structure that supplied image is separated into a first piece of image data, a second piece of image data, and selecting data for selecting the first piece of image data, or the second piece of image data and that separated data is transmitted. At this time, the first piece of image data, the second piece of image data, and the selecting data are subjected to corresponding resolution converting processes and conversion of the resolution using corresponding resolution converting methods. Thus, data which does not require a high resolution can be transmitted at high speed. Data of a type which must have high resolutions may be transmitted at the high resolution. Since the resolutions can be converted to optimum resolutions when data is transmitted, data can be transmitted at high speed. Moreover, deterioration in the quality of the image can be prevented.
Each of the first piece of image data, the second piece of image data, and the selecting data may be omitted from the resolution conversion. Data having the resolution which must be converted may be converted into an adaptable resolution by using an adaptable resolution converting method. When the resolutions of a plurality of data items are converted, the same resolution converting method may be employed or different methods may be employed. When the resolution of the supplied image is maintained for selecting data, a satisfactory quality of the image can be maintained. Also in this case, the resolutions of the first piece of image data and the second piece of image data may be converted. When the same resolution converting method is employed for the first piece of image data, the second piece of image data, and the selecting data when the resolutions are converted, conversion of the resolutions is performede. Then, separation to each data is performed so as to raise the processing speed.